Modules for converting a stairway

ABSTRACT

Modules for converting at least a portion of an existing stairway into an alternating stairway are described. The modules may be installed over an existing stairway to improve accessibility of the stairway for the very young, elderly, ill, injured, or disabled. Installation of the modules creates an alternating stairway presenting a step height that is about one-half the step height of the existing stairway, without appreciably changing the horizontal run or height of the stairway.

RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application Ser. No. 61/601,748 titled “Modules for Converting a Stairway,” filed on Feb. 22, 2012, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to an apparatus and methods for converting at least a portion of an existing stairway into an alternating stairway.

BACKGROUND

Although most standard stairways may be easily navigated by most people, the same stairways can be difficult to navigate by the very young, elderly, ill, injured, or disabled. For example, a standard step height can become a formidable challenge to an elderly or injured person. In some cases, standard stairs can present a “fall risk” to an individual.

There are several approaches to improving accessibility of a stairway. One approach is to install one or more handrails along the stairway, so as to provide an aide and a measure of security or stability for an individual going up or down the stairs. Though providing some sense of security, handrails minimally reduce the physical burden of navigating standard steps. Another solution is to lengthen the horizontal run of the stairway, which can permit adding more steps to the stairway and reducing the height of each step. Another approach is to install a chair lift on the stairway, or an elevator near the stairway. Though these approaches can remove the physical burden and risk of falling, they can be expensive and require special expertise and/or building reconstruction for their installation.

SUMMARY

The present invention relates to modules that may be used to convert at least a portion of an existing stairway into an alternating stairway that provides easier accessibility to the very young, elderly, ill, injured, or disabled. According to one embodiment, the modules are configured so that one module is installed per stair step. In some embodiments, two separate modules may be joined and used per stair step. The modules may be readily installed by a homeowner or an individual without the need for highly skilled labor. The modules may be adapted to convert a full stairway to an alternating stairway in some embodiments. The resulting alternating stairway has effective step heights that are about one-half the step height of the prior stairway. Additionally, the alternating steps are substantially uniformly spaced, step-to-step, for even ascent and descent. In some implementations, the modules may be adapted to convert a portion of a full stairway (e.g., a side portion) to an alternating stairway. The modules may also be readily removed, so that the conversion of a stairway may be temporary (e.g., during a period of temporary illness). Embodiments of the modules may be used indoors or outdoors.

According to one embodiment, a module may be used to convert at least a portion of an existing stairway into at least one step of an alternating stairway. The portion of the existing stairway that is converted may comprise a plurality of successive existing treads with each existing tread of the plurality being displaced from an adjacent existing tread in a fore-aft direction and a vertical height direction. The module for converting the existing stairway may comprise a first step portion having a first tread portion extending a depth in the fore-aft direction and a first riser portion extending a height in the vertical height direction. The first step portion may be configured to be installed over part of an existing tread of the existing stairway so as to provide a first tread of the alternating stairway, and the first tread of the alternating stairway may be displaced in the fore-aft direction from the existing tread. The module may further comprise a second step portion having a second tread portion and a second riser portion, wherein the second step portion is configured to be installed over part of the existing tread of the existing stairway so as to provide a second tread of the alternating stairway.

According to some embodiments, a module for converting at least a portion of an existing stairway into an alternating stairway may comprise a first step portion having a first riser portion and a first tread portion above the first riser at a first height, and further include a second step portion having a second riser portion extending above the first riser portion and a second tread portion above the second riser portion. The second tread portion may be displaced in the fore-aft direction from the first tread portion and located a vertical distance from the first tread portion that is approximately one-half a step height of the existing stairway.

Embodiments further include methods for making modules to convert at least a portion of an existing stairway into an alternating stairway. The portion of the existing stairway that is converted may comprise a plurality of successive existing treads with each existing tread of the plurality being displaced from an adjacent existing tread in a fore-aft direction and a vertical height direction. A method for making a module may comprise forming a first step portion that is configured to be installed over part of an existing tread of the existing stairway so as to provide a first tread of the alternating stairway, wherein the first tread of the alternating stairway will be displaced in a fore-aft direction from the existing tread when installed. The method may further comprise forming a second step portion having a second tread portion and a second riser portion, wherein the second step portion is configured to be installed over part of the existing tread of the existing stairway so as to provide a second tread of the alternating stairway, wherein the second tread portion will not be displaced in a fore-aft direction from the existing tread when installed.

As used herein, displacement of a tread or step of an alternating stairway in a fore-aft direction with respect to an existing tread of an existing stairway means a significant displacement in the fore-aft direct, e.g., a distance greater than approximately two inches. When stating that a tread or step of an alternating stairway is not displaced in a fore-aft direction with respect to an existing tread, the tread or step of the alternating stairway may be located over the existing tread to within about two inches. The terms “approximately” or “about” may be used to refer to dimensions that are within 20% of a relevant value. For example, “approximately one-half of a step height H” would mean any value h falling with a range given by (H/2−0.2H)≦h≦(H/2+0.2H).

The foregoing and other aspects, embodiments, and features of the present teachings can be more fully understood from the following description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The skilled artisan will understand that the figures, described herein, are for illustration purposes only. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. In the drawings, like reference characters generally refer to like features, functionally similar and/or structurally similar elements throughout the various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the teachings. Lines shown in the drawings are for visual aid, and may or may not represent a joining of pieces. In embodiments where molding or casting processes are used, lines that might otherwise represent a joining of pieces may not be present. The drawings are not intended to limit the scope of the present teachings in any way.

FIG. 1A depicts a typical stairway.

FIG. 1B depicts a base module 110 and converter module 120 beside the stairway shown in FIG. 1, according to one embodiment.

FIG. 2 shows a base module 110 in further detail, according to one embodiment.

FIGS. 3A-3C depict converter modules 120 in further detail and as viewed from several directions, according to some embodiments.

FIGS. 3D-3E depict a converter module 120, according to another embodiment.

FIG. 4A shows the stairway of FIG. 1A with a base module 110 installed at the foot of the stairway, according to one embodiment.

FIG. 4B shows the stairway of FIG. 1A with a base module 110 installed at the foot of the stairway and a first converter module installed on a first step of the stairway, according to one embodiment.

FIG. 4C shows the stairway of FIG. 1A with a base module 110 installed at the foot of the stairway and several converter modules installed on steps of the stairway, according to one embodiment.

FIG. 5 depicts a pair of converter modules, according to one embodiment.

The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings.

DETAILED DESCRIPTION

The inventor has recognized that conventional methods for making stairways more accessible to the very young, elderly, ill, injured, or disabled can entail considerable expense, expertise at installing complex equipment, and/or reconstruction of the stairway or proximal area. Further, the inventor has recognized that in some cases (e.g., when the stairway may be in a confined space) it may not be possible to lengthen a horizontal run of a stairway in order to reduce the step height can by adding additional steps. To overcome such potential problems, the inventor has conceived and developed removable modules that can be installed over existing stairs to convert at least a portion of the stairway into alternating stairs wherein each step height, for an individual navigating the alternating stairway, is reduced by about one-half the value of the original stairway. In various embodiments, the converting modules do not appreciably lengthen the horizontal run of the stairway nor change the total height of the stairway.

Alternating stairs differ from standard stairs in that an alternating stairway appears to comprise a pair of stairways abutted side by side that are shifted by about one-half a step. A user traversing the stairs would step on one step of one of the stairways with one foot, and step on a next step of the other stairway with the other foot. One example of an alternating stairway is depicted in the lower portion of a partially converted stairway shown in FIG. 4C.

FIG. 1A illustrates an example of a standard stairway 100, wherein the number of steps may be any value greater than or equal to one, and the step height of each step may be any value between about four inches and about 14 inches. In some embodiments, the step height may be greater than 14 inches. According to some embodiments, the step height may be about 8 inches and the run of a step about 10 inches, or values determined by local building codes. The stairway 100 may be located indoors or outdoors, and may be located in a wet environment (e.g., leading into water). In some embodiments, the stairs may be located on a vehicle (e.g., leading onto a train, in a ship). The stairs may be fabricated from any suitable material (e.g., wood, concrete, plastic, metal, fiberglass, a laminate, a composite material, stone, etc.)

Converter modules 110, 120 for converting the stairway 100, according to one embodiment, are shown beside the stairway in FIG. 18. In some embodiments, multiple types of converter modules may be used in one stairway. The converter modules may include a base converter module 110 and one or more tread converter modules 120. In various embodiments, the converter modules are configured to be mounted next to and/or over the existing stairway so as to convert at least a portion of the stairway into an alternating stairway, as will be described below in reference to FIGS. 4A-4C. The converter modules may be attached to the existing stairway, each other, and/or a wall near the stairway by any suitable fastening means (e.g., screws, nails, hook-and-loop material, adhesive tape, interlocking features). The converter modules may be fabricated from any suitable material (e.g., wood, concrete, plastic, metal, fiberglass, a composite material, a laminate, stone, etc.) In one embodiment, the converter modules are formed from any combination of a plastic, fiberglass, laminate, or composite material so that they can be mass produced at low cost.

FIG. 2 illustrates a base converter module 110 in further detail, according to one embodiment. The base converter module 110 may comprise a lower anchor portion 210 and an upper tread portion 220. The lower anchor portion may include one or more holes 230 or fastening features to permit fastening the base converter module 110 to the foot of the stairway 100. For example, screws may be inserted through holes 230 into the floor at the foot of the stairway. In some implementations, the lower anchor portion may include tabs or right angle features (not shown) located along an edge near a tread riser on the stairway. The tabs or right angle features may have holes that would allow fastening of the base converter module 110 to the tread riser. In some embodiments, the lower anchor portion may extend laterally to an edge of the portion of the stairway that is being converted to an alternating stairway. In some embodiments, the lower anchor portion may extend laterally part way to an edge of the portion of the stairway that is being converted to an alternating stairway. In various embodiments, the height of the upper tread portion 220 above the anchor portion 210 is approximately one-half the height of a step on the existing stairway.

One perspective view of a tread converter module 120, according to one embodiment, is shown in FIG. 3A. Additional perspective views of the tread converter module 120 are shown in FIGS. 3B-3C. The converter module may comprise a lower step portion 301 and an upper step portion 302. The tread converter module 120 may comprise a lower tread portion 310 and an upper tread portion 320. Each tread portion may have a respective face or riser portion 312, 322. The riser portions may be located at a facing edge of the step portions. There may be one or more holes 330 or fastening features to permit fastening the lower tread portion 310 to a step of the stairway 100. In various embodiments, the height of the upper surface of the upper tread portion 320 above the upper surface of the lower tread portion 310 is approximately one-half the height of a step on the existing stairway. In various embodiments, the depth D1 of the upper tread portion 320 is approximately the same as, or may be greater than, the depth of a tread on the existing stairway 100. In some implementations, the depth D1 of the upper tread portion 320 may be less than the depth of a tread on the existing stairway. In various embodiments, the depth D2 of the lower tread portion 310 is approximately the same as, or may be greater than, one-and-one-half the depth of a tread on the existing stairway 100. According to some embodiments, the depth D2 is approximately one-and-one-half the depth of a tread on the existing stairway.

In some embodiments, exposed corners 325, 225 of the modules may be rounded. The rounding may be provided as a safety feature in the event of a fall on the alternating stairs, so as to prevent contact with a sharp feature. In some of the drawings, e.g., FIG. 3B, the rounding may not be shown to simplify the drawing. Although many embodiments may include rounding of the exposed corners, some embodiments may not include rounding as shown in FIG. 3C and FIG. 3D.

With reference to FIG. 3C and FIG. 3D, in some embodiments, there may be additional or alternative fastening features located at any combination of rear edges 340, 350, lower edges 360, 370, and side edges (e.g., edges adjacent a wall) of each converter module. The fastening features may be holes for inserting screws or nails, or may be tabs (e.g., right-angle protrusions) with holes extending up from or away from the edges so as to permit insertion of a screw or nail into an adjacent surface (e.g., a riser or tread of the existing stairway or an adjacent wall). In some embodiments, the fastening features may include interlocking elements (e.g., a recessed feature near a rear edge 340, 350 that mates and interlocks with a protruding feature near a lower edge 360, 370 of an adjacent module). The holes or fastening features may be located such that they become covered and hidden from view when a next module is installed.

Portions of the modules that are hidden from view when installed (e.g., back riser 332 and rear lower portion 311 in FIG. 3A) may not be uniformly solid slabs of material. For example, as depicted in FIG. 3B, holes or voids may be present in the hidden portions to reduce the amount of material used to fabricate a module and/or to reduce a weight of the module. This may reduce an amount of material needed for making the modules when they are cast or molded. In some cases, holes or voids may be drilled into, cut from, or stamped out of a formed module.

In some embodiments, a module 110 or 120 may be formed by a molding, casting, or metal forming process, such that the module is formed as a continuous piece of material, or from a few pieces of material. When formed as a continuous piece of material, line in the drawings showing joined pieces may not be present. For example, the lines in FIG. 3B that indicate joining of riser pieces may not be present when the riser portions or the entire module is formed as a continuous piece. In some embodiments, a module may be formed from several pieces of similar or different materials, e.g., polymer risers and metal treads.

To accommodate stair steps of various heights, in some embodiments, the riser portions 312, 322 of each converter module may be made adjustable or partially removable. According to one embodiment, each riser portion may comprise two pieces (e.g., overlapped boards or plates positioned side by side) that may slide with respect to each other in a vertical direction and be fixed by screws at a desired riser height. In other embodiments, each riser portion may be made of a material that can easily be cut to a desired height. In yet other embodiments, each riser portion may be scored at various heights such that a lower portion may be broken off to obtain approximately a desired height. In some embodiments, with reference to FIG. 3E, the tread portions 310, 320 may be removable from the module (e.g., fastened by screws or interlocking features to the respective riser portions). For embodiments for which the tread portions are removable, the upper portions of the risers may also be cut or scored for breaking off to accommodate stair steps of different heights.

In some implementations, it may not be necessary to modify the modules for stair steps of various tread depths. For example, the modules may have tread portions 310, 320 with depth dimensions greater than the existing stairway's step tread depth. When installed, the modules may overlap in a horizontal direction to accommodate different tread depths. Though it may not be necessary to modify the modules for stair steps of various tread depths, the tread portions and/or riser portions of the modules may be cut or broken off at the rear edges (e.g., edges 340, 350) of the module, in some implementations. In some embodiments, the modules are fabricated with dimensions that conform to local building codes (e.g., the modules are sized to be installed over stairs having standard rise and run values), or the modules are fabricated with dimensions that conform to the existing stairway.

Though not shown in the drawings of FIG. 3A-3E, each converter module may include a nosing feature or extension of the tread portions 310, 320 out over the respective risers. With reference to FIG. 3D, a nosing feature or tread edge 314, 324 may extend out over each respective riser portion 312, 322 by a distance that may be determined by local building codes. The nosing may extend out over a riser by any amount up to approximately two inches in some embodiments. As noted above, the tread portions 310, 320 may be removably attached to the riser portions of the converter modules. Removal of the tread portions may facilitate cutting of the tread portions and/or riser portions of the module for adapting the module to any stairway.

FIG. 4A depicts an existing stairway 100 and a base module 110 installed at the foot of the stairway. The base module 110 may be fastened to a floor at the base of the stairs using screws and/or fastened to a riser of the first step of stairway 100 with fastening features (e.g., screws through tabs or a right-angle feature as described above). The height of the module's step may be approximately one-half the height of a step on the existing stairway. In some embodiments, it may be more than one-half the height of a step on the existing stairway, and the tread converter module 120 may be configured to accommodate the difference from a value of one-half the step height.

FIG. 4B illustrates the same stairway 100 with a first converter module 120 installed at a first step and adjacent to the base module 110. The converter module 120 may be fastened to a tread of the first step using screws and/or fastened to a riser of the first step of stairway 100 with fastening features (e.g., screws through tabs as described above). In some embodiments, the first converter module 120 may register to, and fasten only to, the base module (e.g., with interlocking features (not shown) that connect the first converter module to the base module). In various embodiments, the lower tread portion 310 of the first converter module is at a height above the upper tread portion 220 of base module 110 of about one-half the height of a step height of stairway 100. As noted above for the first converter module, the height of the upper surface of the upper tread portion 320 above the upper surface of the lower tread portion 310 is about one-half the height of a step on the existing stairway 100. Additionally, the run for each step is approximately the same. For example, the fore-aft distance between each riser or leading edge of successive alternating steps is approximately the same. In some implementations, the fore-aft distance between successive risers on the alternating steps is approximately one-half the tread depth of the existing stairway. FIG. 4C shows the same stairway 100 with additional converter modules 120 installed over additional steps.

When ascending the stairway portion converted to an alternating stairway (left portion of stairway as depicted in FIG. 4C), an individual may place a left foot on the upper tread portion 220 of base module 110, a right foot on the lower tread portion 310 of the first converter module, then the left foot on the upper surface of the upper tread portion 320 of the first converter module, and so on up the stairs. It will be appreciated that each step height by an individual ascending the alternating stairway will be approximately one-half the step height that would occur on the original stairway, making the stairway more accessible to the very young, elderly, ill, injured, or disabled. This can be understood by considering an individual walking up the alternating stairway (left portion of the converted stairs in FIG. 4C) as compared with an individual walking up only the right portion of the stairway. Further, the horizontal run R of the stairway is not significantly increased by the addition of the converter modules.

In FIG. 4C, the converter modules are shown as being asymmetric. For example, the tread on one side of the stairway is wider than the tread toward the other side of the stairway. In some embodiments, the converter modules may be symmetric. In some embodiments, the converter modules may not be configured to cover the full width of a stairway.

The embodiment of converter modules 120 and base module 110 shown in FIG. 4C may be used to convert only a portion of a stairway into an alternating stairway, while preserving a remaining portion of the standard stairway with standard step heights. Converting a portion of a stairway into alternating stairs may be desirable where the stairs are used both by healthy individuals and the very young, elderly, ill, injured, or disabled. For example and with reference to FIG. 4C, a healthy individual may ascend and descend the stairway, once fully converted, using the right portion of the stairway that retains the same step heights as the original stairway. A person with a disability may ascend the alternating stairway on the left, and descend using either the alternating stairway portion or the right portion of the stairway. (Similarly, converter modules narrower than the full width of a stairway would, once installed, leave a portion of the existing stairway exposed for normal use.)

As can be seen in FIG. 4C, when the converter modules are installed in some implementations, the resulting treads of the alternating stairway are displaced in a fore-aft direction from the existing stairway's treads. For example and also referring to FIG. 4B, the lower tread portion 310 of the converter modules 120 provide treads of the alternating stairway that are displaced in a fore-aft (or “run” direction) about one-half the width of the tread of the existing stairway. This displacement, in combination with the configuration of the upper tread portion 320, provides for substantially equal tread depth and step-to-step distance on the alternating stairway. The step-to-step distance is substantially equal in terms of step height and fore-aft distance between successive pairs of step risers or leading edges of the steps.

When a portion of a stairway is converted, the modules may be designed to form an alternating stairway to a side of the stairway that has a railing. This would allow an individual traversing the alternating stairway to also have the aid of a hand rail.

In some implementations as depicted in FIG. 5, the converter modules may be fabricated as a pair of separate modules or step portions 501, 502 to be installed in combination so as to convert at least a portion of a stairway into an alternating stairway and/or to the abutting module. The modules may be installed on a step so that they abut, e.g., at line 505 in FIG. 5. The first module 501 may have a first riser portion 512 and a first tread portion 510. The first module may be configured to be attached, with screws or any suitable fastening means, to a step of a stairway and/or to the abutting module. The second module 502 may have a second riser portion 522 and a second tread portion 520. The second module 502 may be configured to be attached, with screws or any suitable fastening means, to the same step in combination with the first module, such that when the second module is attached to the step the second tread portion 520 is at a height different than the first tread portion 510. In various embodiments, the height difference is about one-half the height of a step height on the existing stairway. The two modules 501, 502 may be configured to be attached together in some implementations. In some embodiments, the depth of the tread portion of the first module 501 is greater than the depth of the tread portion of the second module 502. The method by which modules may be attached may include any suitable fastening means described above. Forming separate modules 501, 502 may permit more compact packaging and storage of multiple modules.

In some embodiments, one or more converter modules may include one or more upright balusters configured to support a railing. A hand rail may be attached to the one or more balusters so that an individual traversing the alternating stairs may use the hand rail. Such a railing may be useful where the modules are used to convert a portion of a very wide stairway that is indoors or outdoors.

Although each converter module may be shown or described as having holes or fastening features for fastening the converter module to the existing stairway, each converter module need not have holes or fastening features for fastening the converter module to the existing stairway, or the holes or fastening features may not be used for each converter module. In some embodiments, only every N^(th) module may be fastened to the existing stairway, where N is an integer value greater than 1. According to some embodiments, converter modules may have interlocking features such that a successive module securely registers and connects to an adjacent converter module. Accordingly, some converter modules may be securely positioned in the alternating stairway without the need for fastening (e.g., with a screw) each module to the existing stairway.

The converter and base modules may be manufactured in any suitable manner. In some cases, they may be assembled, manually or by machine, from pieces (e.g., from riser, tread, and edge pieces). In some implementations, the modules may be formed using any suitable molding or preform process (e.g., injection molding, casting, fiberglass or laminate manufacturing processes).

The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described in any way.

While the present teachings have been described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments or examples. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art.

The claims should not be read as limited to the described order or elements unless stated to that effect. It should be understood that various changes in form and detail may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims. All embodiments that come within the spirit and scope of the following claims and equivalents thereto are claimed. 

What is claimed is:
 1. A first module for converting at least a portion of an existing stairway into at least one step of an alternating stairway, the portion of the existing stairway comprising a plurality of successive existing treads with each existing tread of the plurality being displaced from an adjacent existing tread in a fore-aft direction and a vertical height direction, wherein the first module comprises: a first step portion having a first tread portion extending a depth in the fore-aft direction and a first riser portion extending a height in the vertical height direction, wherein the first step portion is configured to be installed over part of an existing tread of the existing stairway so as to provide a first step of the alternating stairway, and wherein the first step of the alternating stairway is displaced in the fore-aft direction from the existing tread and has a depth approximately equal to an existing tread depth.
 2. The first module of claim 1, wherein the displacement of the first step of the alternating stairway in the fore-aft direction is approximately one-half a depth of the existing tread, the depth of the existing tread being in the fore-aft direction.
 3. The first module of claim 1, wherein the depth of the first tread portion is approximately one-and-one-half times a depth of the existing tread.
 4. The first module of claim 1, further comprising a second step portion having a second tread portion and a second riser portion, wherein the second step portion is configured to be installed over part of the existing tread of the existing stairway so as to provide a second step of the alternating stairway.
 5. The first module of claim 4, wherein the second step of the alternating stairway is positioned at a vertical height from the first step of the alternating stairway that is approximately one-half the step height of the existing stairway.
 6. The first module of claim 4, wherein a depth of the first step of the alternating stairway is approximately equal to a depth of the second step of the alternating stairway.
 7. The first module of claim 4, wherein a width of the first step of the alternating stairway is greater than or equal to a width of the second step of the alternating stairway, the widths being in a direction transverse to the fore-aft direction.
 8. The first module of claim 4, further comprising a second module as claimed in claim 4, wherein when installed adjacent to the first module third and fourth steps of the alternating stairway are formed including third and fourth riser portions, wherein a fore-aft distance measured between any two adjacent pairs of riser portions is substantially equal.
 9. The first module of claim 8, further comprising fastening and/or interlocking features that enable the first module to be attached to one or both of the existing stairway and the second module when installed on the existing stairway.
 10. The first module of claim 9, wherein at least some of the fastening and/or interlocking features are located such that they are covered and hidden from view by the second module.
 11. The first module of claim 4, wherein the first and second riser portions are adjustable.
 12. The first module of claim 4, wherein the first step portion and the second step portion are formed as separate, disconnected pieces that are configured to be joined together before or when installed on the existing stairway.
 13. The first module of claim 4, wherein the module comprises at least one material selected from the following list of materials: wood, concrete, plastic, metal, fiberglass, a composite material, a laminate, and stone.
 14. The first module of claim 4, further comprising a separate base module configured to be installed at a base of the existing stairway and provide one base step of the alternating stairway.
 15. The module of claim 14, wherein the base module comprises: an anchor portion for attaching the base module to a floor or base riser of the existing stairway; and an upper tread portion that is spaced above the floor by approximately one-half the step height of the existing stairway.
 16. A method for making a module for converting at least a portion of an existing stairway into at least one step of an alternating stairway, the portion of the existing stairway comprising a plurality of successive existing treads with each existing tread of the plurality being displaced from an adjacent existing tread in a fore-aft direction and a vertical height direction, the method comprising: forming a first step portion that is configured to be installed over part of an existing tread of the existing stairway so as to provide a first step of the alternating stairway, wherein the first step of the alternating stairway is displaced in a fore-aft direction from the existing tread; and forming a second step portion having a second tread portion and a second riser portion, wherein the second step portion is configured to be installed over part of the existing tread of the existing stairway so as to provide a second step of the alternating stairway, wherein the second step is not displaced in a fore-aft direction from the existing tread.
 17. The method of claim 16, wherein when the first and second step portions are installed over the existing tread, a vertical height from the first step of the alternating stairway to the second step of the alternating stairway is approximately one-half a step height of the existing stairway.
 18. The method of claim 16, further comprising: forming a base module configured to be installed at a base of the existing stairway and provide one base step of the alternating stairway, wherein the base module comprises: an anchor portion for attaching the base module to a floor or base riser of the existing stairway; a base riser portion; and an upper tread portion that is spaced above the floor by approximately one-half a step height of the existing stairway.
 19. A module for converting at least a portion of an existing stairway into an alternating stairway, the portion of the existing stairway comprising a plurality of successive existing treads with each existing tread of the plurality being displaced from an adjacent existing tread in a fore-aft direction and a vertical height direction, the module comprising: a first step portion having a first riser portion and a first tread portion above the first riser at a first height; and a second step portion having a second riser portion extending above the first riser portion and a second tread portion above the second riser portion.
 20. The module of claim 19, wherein the second tread portion is at a height above the first tread portion that is approximately one-half a step height of the existing stairway, and the first riser portion is spaced a fore-aft distance from the second riser portion that is approximately one-half a tread depth of the existing stairway. 